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Stress hormones predict a host superspreader phenotype in the West Nile virus system

September 12, 2017

Glucocorticoid stress hormones, such as corticosterone (CORT), have profound effects on the behaviour and physiology of organisms, and thus have the potential to alter host competence and the contributions of individuals to population- and community-level pathogen dynamics. For example, CORT could alter the rate of contacts among hosts, pathogens and vectors through its widespread effects on host metabolism and activity levels. CORT could also affect the intensity and duration of pathogen shedding and risk of host mortality during infection. We experimentally manipulated songbird CORT, asking how CORT affected behavioural and physiological responses to a standardized West Nile virus (WNV) challenge. Although all birds became infected after exposure to the virus, only birds with elevated CORT had viral loads at or above the infectious threshold. Moreover, though the rate of mortality was faster in birds with elevated CORT compared with controls, most hosts with elevated CORT survived past the day of peak infectiousness. CORT concentrations just prior to inoculation with WNV and anti-inflammatory cytokine concentrations following viral exposure were predictive of individual duration of infectiousness and the ability to maintain physical performance during infection (i.e. tolerance), revealing putative biomarkers of competence. Collectively, our results suggest that glucocorticoid stress hormones could directly and indirectly mediate the spread of pathogens.

Publication Year 2017
Title Stress hormones predict a host superspreader phenotype in the West Nile virus system
DOI 10.1098/rspb.2017.1090
Authors Stephanie Gervasi, Sarah Burgan, Erik K. Hofmeister, Thomas R. Unnasch, Lynn B. Martin
Publication Type Article
Publication Subtype Journal Article
Series Title Proceedings of the Royal Society B
Index ID 70190676
Record Source USGS Publications Warehouse
USGS Organization National Wildlife Health Center